Billet heating furnace



June 5, 1956 F. o. Hass 2,749,108

BILLET HEATING FURNACE Filed Aug. 2o, 1952 INVENTOR. FREDERICK O. HESSATTORN EY.

BILLET HEATINGrFURNACE YiFrederic'O."Hess, Philadelphia, V'"Pa.,assignor to 'Selas JCorporation. of.Amerca,- Pliladelphia, Pa., acorporaftionof Pennsylvania Application August20, 1952, Serial No.305,458

'5 Claims. i(Cl.-263-6) .The present invention relates to furnaces, andmore .particularly to, furnaces through which .metaLbodies suchVasingots and billets are moved one after another to be heated.

`.It is an object of the .present invention to provide ya furnace .inwhich the objects to-be heated are carried therethroughon an overhead-conveyor. VItis afurther objectof the inventionto provide `a furnacehaving a `plurality of .openings :or doors in .the .bottom through,whichvthe objects beingheated can be removed if they l 'drop "from 'theconveyor.

`The.inven`tion includes a v'furnace having a chamber thatis directly`fired by.apluralityof burners. The-roof of the chamberhas .a slot.extending lengthwise thereof through which conveying mechanism extendsto support Vthe work so that it maybe heatedevenly on all sides.

'From time to-time ythe work pieces .may drop from Vthe conveyorandobstruct the'furnacechamber. The floor .of the chamber is ythereforevprovided with .or made of a plurality of doors that can be openedindividually so that the workpieces thereon may easily be.rernoved.

The various features of novelty whichcharacterize my vinventionarepointed out Wi'thparticularity in the claims annexed to land formingapart of .this specification. For better understanding of the invention,however, .its advanges and specific objects attained with its use,`reference 'should be had to the 4accompanying drawings and descriptivevmatter in which l have villustrated .and described a preferredembodiment of the invention.

IVln the'drawings:

Figure l is a section View taken throughthe furnace on line 1-'1ofFigure'Z; and

Figure'Z is .a transverse section of therfurnace.

Referring to the drawings, there are shown a pair of foundation .beams lextending longitudinally .of the furnace. Attached to these beams atspaced ,points are vertically extending-supports 2 uponwhich'structureforming :a 'furnacevchamber .is mounted. This chamberis builtinilaccordance withordinary. furnace 'practice and-includes f 'a'meta'lbacking ,sheet 4,around.the'-sitlesfand top thereof. This backing serves.to .supporta furnace linin-gof suitfable refractory Vmaterial 5 of .athickness and composiftion to 0withstand .the vtemperature fof thefurnace. 'The ltop of fthe furnace rstructure is yThung '..from thesupports `2 iby means-of braces 6 weldedtheretolwhich lextend -in-Mardly from each side thereof. The ffurnace can be heated by anysuitable burners but is preferably heated by burners of the type whichproduce radiant heat such as those disclosed in Furczyk Patent2,561,793, issued on July 24, 1951. These burners each include a ceramicblock 7 which is embedded in and forms part of the furnace wall. Eachblock is provided on its face in the furnace chamber with a cup-shapeddepression 8 into the base of which extends a distributor 9. Air and gasunder suitable pressure are supplied through the distributor from whichit is discharged in a plurality of radially directed jets that burnalong the surface of the cup 8 to heat the same to incandescence.Radiant heat from 2,749,108 Fatented June a5, 1956 thereup, '-as well asvhot ,products .of ``combustion, fheat the walls -of the'furnace chamberto:incandescence and transfer 'heat tto the work AEach of these "burnersis supplied individually through a pipe Vllfanditheburners -in eachrowmay be'connected to amanifold 1'2. The -supplyvof fuel toeach burner can'be-'adjusted individually by a valve l. As :shown therein, vthe.burners :are

` staggered on opposite zsides tof the f furnace `chamber, so

that the work is heated evenly throughoutiits entire .area .as it'isbeing-moved longitudinallyzthroughthechamber.

`If desired, suitable automatic :controls can be provided to regulatethe furnaceternperature The top ofthe chamber vis `provided vwith:a-eentrally .extending slot -14 alongthe .upperedgesxof `whichfare :Io-

cated water cooled 'passages `15. These'passages'arefsupplied'withcooling water at .oneend bypipes I6, andthe Vcooling water is Vremovedat the'oppositefend of thefurnace.

The .bottom or door of the furnace -comprises'a iplurality of doorswhich can be opened 'togive accesstofthe furnace chamber.-Eachofthesedoors includes a metal frame in'fonniof a casting 17 thatisJfilled with a Ysuitable refractorymaterial '18, and lwhiclrextendsfrom the low`er edge of voneside wall to the lower edge of the lother.The frame -17 is pivoted at -19on api-vot that lisparallel to the sidewalls,'so that'the doors -c'an be tilted YVfrom their fullline totheir-dotted line positions in -Figure r1 and .thereby permit removallof --ingots or billets when such is necessary. Each-casting-isgprovided-w-ith Tan=arm 21 extending `to the right, -as shown in v'Figure 4l ofthe drawing, and to -which is vattached-'a counterweight 22 that isheavyenough normall-yrto-h'oldtheidoorin closed position. IThiscounterweight may be supplementedwith a spring if desired. yIn ksortiecases it -may'be desirable to lockthe doors in=their closed .position.This :is -accomplished by aflatchplate 23 extendingfrom the left side ofcasting 17, which 'plate *is engaged by -a latch '24 that ris -pivotedonVthe yright side yof the furnacevframe "The upper end of .the rod isrvfastened to a carrier L9 that 'is .provided with Vrollers [31which-engage -the -filanges of a track 32. rlhis track `extendslengthwise Aof ythe Jfurnace and is supported by crosspieces 33which-arcattachedto'the upper ends of the vertical supports 2. :Each ofthe billet carriers is provided with a yheat seal to 'preventloss dfheat`thro'ug'hfthe roof or" the'lfurnace which `includes a ishield'through which 'the rod .'27 extends. `rPhe Vrod l-is *provided 'with a'collar I'35 i'n order to keep the shield 3:4 from falling below va'predetermined point 'Whe'n the #carriers are tout 1 d'f the ffurnace.Skid plates 35 extend along the upper surface of the channels 15 for theshield to ride along as the carrier is moving a billet through thefurnace.

The ends of the furnace chamber are closed by doors similar to the oneshown at 37 in Figure 2. The door is guided for vertical movement and isopened by lowering it below the oor level. The door is raised andlowered by counterweighted cables 38 that pass over pulleys 39 attachedto the furnace supported structure.

Prior to the time the billets 26 are heated, a ring 2S or some similarsupporting device is fastened to the top thereof as by welding. Thebillets are then placed on the hooks of the carriers 27 and are ready tobe heated. Periodically, the door 37 is opened and a carrier is rolledalong the track to move a billet into the furnace. As the billetsprogress through the furnace, they are heated to a forging or extrusiontemperature in the neighborhood of 2250 F. This heat is produced by theburners predominately in the form of radiant heat, but also by hotproducts of combustion. Ordinarily, the cups of the burners of this typeare heated to a temperature in the neighborhood of 2800 F., and thefurnace chamber itself will be a few hundred degrees lower or in theneighborhood of 2500 F. With a temperature gradient of this type, abillet of alloy steel 6.35 inches in diameter and 28 inches longweighing 250 pounds can be brought up to a forging temperature in 2J:-minutcs or less. The radiant heat produced by the furnace will heat thebi.- lets evenly throughout their volume, so that by the time they areremoved from the other end of the furnace, they can be placed directlyin a forging or extrusion press. The fuel-air ratio supplied to theburners is controlled so that there is normally a neutral atmosphere ofproducts of combustion in the furnace chamber, and thus there ispractically no scale formed on the billets during the heating process.

From time to time defective welds will be formed between the supportingmembers 26 and the billets 26. A billet having one of these defectivewelds will frequently fall from the conveyor, and will block the passagethrough the furnace chamber if provision is not made for removing thesebillets. Since the bottom ot' the furnace consists of a plurality ofdoors that are counterbalanced to a closed position they will openindividually when a billet falls on them. The billet is thereby quicklyremoved from the furnace without losing a great amount of heat from thechamber and without interrupting the heating process of the remainingbillets. lf the latches 24 are being used, it is only necessary for theoperator to release the latch of the door upon which the fallen billetis resting in order for it to be removed.

From the above, it will be seen that l have provided a furnace throughwhich billets are conveyed by an overhead structure one after the otheras they are being heated. The furnace oor consists of a plurality ofdoors through which individual billets can be removed, if for somereason they should fall from the conveying mechanism. The billets can bemoved directly through the furnace on a production line basis to a pointupon which work is performed on them.

While in accordance with the provisions of the statutes, I haveillustrated and described the best form of embodiment of my inventionnow known to me it will be apparent to those skilled in the art thatchanges may be made in the form of the apparatus disclosed withoutdeparting from the spirit and scope of the invention as set forth in theappended claims, and that in some cases certain features of my inventionmay be used to advantage without a corresponding use of other features.

What is claimed is:

l. In a furnace system, the combination of structure forming anelongated furnace chamber having side walls, a roof and a oor said roofbeing provided with a slot extending lengthwise thereof and throughwhich is adapted to extend a conveyor to carry billets to be heated insaid chamber, said oor being formed of a plurality of sections extendingbetween the lower edges of each side wall, means to mount each sectionfor movement between a first position in which it closes the spacebetween said side walls and a second position in which said space isopen, and means to bias said sections normally to their first position,said oor sections moving to their second position against the action ofthe biasing means to discharge billets dropped by the conveyor.

2. ln a furnace system, the combination of structure 'forming anelongated chamber having side walls and a roof, said roof being providedwith a slot extending ccntrally thereof from one end to the other, aplurality of burners located in said side walls to supply heat to saidchamber, a oor for said chamber being formed of a plurality of doorsextending between the lower edges of said side walls, means to mountsaid doors for pivotal movement around an axis below and parallel to oneof said side walls, and latch means operative to hold said doors inclosed position extending between said side walls.

3. A furnace comprising vertical supports, structure mounted on saidsupports forming an elevated furnace chamber substantially rectangularin section, said structure forming side Walls, burners for heating saidchamber mounted in said side walls, said structure also including meansforming a roof for said chamber with the roof having a slot runninglengthwise thereof from end to end through which a conveying mechanismfor carrying work to be heated is adapted to extend, and said structureincluding means forming a bottom for said chamber consisting of aplurality of sections, pivot means to support each of said sections forswinging movement parallel to one of said sides whereby when work isdropped from the conveying mechanism it can be removed trom the chamberthrough one of said sections, and means to bias each section normally toits closed position against the lower edges of said sides.

4. The combination of claim 3 including means to latch positively eachof said sections in its closed position.

5. Apparatus for heating billets comprising structure forming the sidewalls and roof of an elongated furnace chamber, said roof being providedwith a slot extending from one end to the other thereof, a plurality ofdoors forming the oor of said chamber, each door engaging the lower edgeof each of said sides, means to mount each door below one of said sidesand for pivotal movement around an axis parallel to said side, means tomaintain each of said doors in its normal closed position, and a door ateach end of said chamber through which dork to be heated can be moved asit is carried by mechanism that is adapted to extend through said slot.

References Cited in the file of this patent UNITED STATES PATENTS836,679 Garred Nov, 27, 1906 1,773,049 Lobley Aug. 12, 1930 1,858,434Colby May 17, 1932 1,586,599 Bohler June 1, 1936 2,062,642 Darrah Dec.1, 1936 2,224,460 Mortenson Dec. 10 ,1940 2,269,827 Mendoza Jan. 13,1942 2,272,966 Dany Feb. 10, 1942 2,478,964 Cooper et al Aug. 16, 1949

